Production of low carbon steel wire from a direct melt low carbon alloy process has been known for many years. Fibers may be produced directly from a molten metal alloy stream impinged upon a chill block which is called melt spinning. Another well-known process which employs a rotating wheel or disk which contacts a pool of molten metal is referred to in the industry as melt extraction.
A particularly important application for fiber forming processes is the production of low cost steel fiber for use as a concrete reinforcing agent. One of the primary problems in producing such fiber is achieving the necessary ductility and strength in the final product while keeping the cost of manufacture at sufficiently low levels to be of commercial usefulness.
The melt extraction process is generally preferred for producing such low cost steel fibers compared to melt spinning.
In order to achieve sufficient ductility in this process, the cooling rates must be controlled properly to assure a quality product. Therefore, prior attempts to utilize this process have devised relatively elaborate quenching systems to attempt to obtain the necessary control of ductility in the fiber product. However, it has been a very difficult problem to obtain the necessary consistency of result using such systems. It appears that the typical low carbon steel available as scrap which is used in such processes for obvious economic necessity, is very critical to quench rates relative to obtaining the ductility required in the final product. In view of the necessity that low cost manufacture be maintained as well as low cost of raw material, this problem has been a major limiting factor in the efficient production of low carbon steel fiber from melt extraction which possesses the necessary levels of both strength and ductility for concrete reinforcing applications.